This proposed study will make use of Public Use Sample files, derived from the 1940, and 1960 through 1980 decennial censuses to broaden our understanding of the dynamics of internal migration, by analyzing population redistribution trends within and between metropolitan and nonmetropolitan areas between 1935 and 1980. Specifically, interest centers on analysis of (1) changes in the volume and efficiency of migration streams occurring within and between metropolitan and nonmetropolitan areas by region, race, and sex; (2) trends in migration selectivity (origin) and differentials (destination) with respect to age and educational attainment in the redistribution of population within and between metropolitan and nonmetropolitan areas by race and sex; and (3) the changing role of migration types in population redistribution trends within and between metropolitan areas by race, sex, age and educational attainment. Previous efforts to study migration streams within and between metropolitan and nonmetropolitan sectors in a longitudinal framework have been seriously hampered by the limited availability of requisite data. This proposed study seeks to remedy this deficiency.